Effect of (-)-hydroxycitrate on fatty acid synthesis by rat liver in vivo.

Methods---Rats were obtained from the Charles River Breeding Laboratories, North Wilmington, Massachusetts. Upon receipt the animals were placed on a scheduled diet consisting of Purina Laboratory chow (0.5-inch Checkers), Ralston Purina Company, St. Louis, Missouri, given to one animal per cage, from 9 a.m. to 12 noon. Water was made available ad libitum. The animals were kept in an artificially lighted room, with the light on from 6 a.m. to 6 p.m. The room temperature was 24’. Although rats are normally nocturnal feeders, the above schedule of light and food yielded very reproducible rates of fatty acid synthesis. I am indebted to Dr. 0. Neal Miller for informing me in advance of publishing his own work that this regimen leads to much more reproducible rates of fatty acid synthesis than are obtained when the animals receive food ad l&turn. After 7 to 10 days on the chow diet the rats were fasted for 45 hours-that is to say, they missed one scheduled feeding-and they were then fed a scheduled diet high in fructose or glucose (2) for 10 to 15 days. Weights of the animals at the time of use are indicated in the legends. Unless otherwise indicated, experiments with the rats were started 3.5 to 4 hours after the animals started their last feeding schedule. When indicated rats were injected with 2 to 20 ~-JM sodium (-)-hydroxycitrate, pH about 7.4, in amounts indicated in the legends. Controls received an equal volume of